fn export_sys_vars()

in aws-lc-rs/build.rs [40:78]

• 27 lines of code
• 7 McCabe index (conditional complexity)

fn export_sys_vars(sys_crate: &str) {
    let prefix = if sys_crate == "aws-lc-fips-sys" {
        "DEP_AWS_LC_FIPS_"
    } else {
        "DEP_AWS_LC_"
    };

    let mut selected = String::default();
    let mut candidates = vec![];

    // search through the DEP vars and find the selected sys crate version
    for (name, value) in std::env::vars() {
        // if we've selected a prefix then we can go straight to exporting it
        if !selected.is_empty() {
            try_export_var(&selected, &name, &value);
            continue;
        }

        // we're still looking for a selected prefix
        if let Some(version) = name.strip_prefix(prefix) {
            if let Some(version) = version.strip_suffix("_INCLUDE") {
                // we've found the selected version so update it and export it
                selected = format!("{prefix}{version}_");
                try_export_var(&selected, &name, &value);
            } else {
                // it started with the expected prefix, but we don't know what the version is yet
                // so save it for later
                candidates.push((name, value));
            }
        }
    }

    assert!(!selected.is_empty(), "missing {prefix} include");

    // process all of the remaining candidates
    for (name, value) in candidates {
        try_export_var(&selected, &name, &value);
    }
}